Frik Els , Editor

Shares in China-focused miner Silvercorp Metals slumped over 7% on Monday after British Columbia security regulators said they were joining the investigation into an anonymous letter accusing the company of a $1.3 billion fraud. Silvercorp was forced on Friday 2 September to make public the letter and at the same time disclosed that someone had built up a short position of 23 million shares – more than 13% of the number outstanding. The firm with projects in China and Canada plunged after the news broke and Monday's drop brings year to date losses close to 40% despite the firm's ongoing buyback programme.

The Australian reports BHP Mitsubishi's decision to bypass a thoroughly resistant troika of unions by seeking a direct employee ballot on a new three-year enterprise agreement takes the world's number one miner into deeply uncharted industrial relations waters. The move comes after nine months of fruitless negotiations and 11 different offers – including annual pay rises of 5% and a $15,000 bonus – all of which were rejected by the unions which will now resume strikes. The six mines operated by BHP Mistubishi have a combined output capacity of more than 58 million tonnes per year of mostly metallurgical coal, representing about a fifth of annual global trade.

Gold for December delivery – the most actively traded contract – fell 2.4%  or $45, to $1,815 an ounce on the Comex division of the New York Mercantile Exchange by lunchtime on Monday failing to capitalize on its safe-haven status as investors were forced to raise cash to cover losses on equity markets. The benchmark Dow Jones Industrial Average suffered another day of heavy selling, declining more than 120 points in volatile trade while European and Asian markets were battered after the deputy finance minister of Greece said the debt-laden country has cash to operate only until next month. Germany was readying measure to protect its banks against a Greek default while France's financial institutions were downgraded because of its exposure.

Stornoway Diamond Corporation involved in the discovery of over 200 kimberlites in seven Canadian diamond districts will join S&P/TSX SmallCap Index at the end of the week, a move which should increase the appeal of the counter among institutional investors. It's a new milestone for Stornoway which flourished under the leadership of Eira Thomas, the renowned diamond explorer whose spectacular success in the 90s transformed Canadian diamond mining. Thomas left in August following the acquisition of Stornoway's lead asset – the 100%-owned Renard Diamond Project – on track to become Quebec's first diamond mine.

Alaska's Pebble deposit presents big problems for Northern Dynasty, the junior Canadian miner that wants to cash out of its sole asset. Pebble has an eye-popping recoverable resource of 67 million ounces of gold and 55 billion pounds copper with some molybdenum thrown in for good measure which at today's prices is worth over $300 billion in total. The Vancouver company shares the venture with Anglo-American but the $4.7 billion development costs could be too rich even for the London-listed giant's blood. Apart from the problem of finding a heavyweight buyer for its 50%, Dynasty also faces opposition from a $150 million a year salmon fishery near the site and local environmental protesters who have enlisted the support of Hollywood celebrities like Robert Redford.

Reuters reports prices of most rare earth elements – used in consumer electronics, defence and green energy industries – have risen since Wednesday after of local government crackdown on mining, with three major producers slated for closure. The news follows an announcement from the EU that it is building a stockpile of a variety of REEs and that a high-level meeting of officials from Europe, the US and Japan will take place in Washington early next month to discuss supply security. The price of some REEs such as samarium oxide used in jet fighter electrical systems has increased 25-fold in just three years.

Authorities in Belgium are investigating a case that may turn out to be the country's largest ever fraud. De Tijd this week published some of the names from a list of 170 of Antwerp diamond traders who it claims are being investigated by authorities for spiriting almost $1 billion (€700 million) in unpaid taxes into secret Geneva bank accounts. Approximately 80% of the total world production of rough diamonds is traded by the 185 gem companies operating in Antwerp (pictured) and 50% of the globe's polished diamonds pass through the Flemish town. The Antwerp traders are among a much larger roster of at least 24,000 HSBC Private Bank clients from Canada, India and Germany under investigation by French authorities since 2009.

Amid dire predictions about job losses and the drying up of investment in the sector due to a proposed carbon tax come more bad news for Australia's coal miners. Platts reports New South Wales plans to increase the royalties it receives from coal companies to offset some $400 million in extra costs to the state's coal-fired electricity generators due to the very same federal government carbon levy. Around 95% of NSW's royalty revenue comes from coal mines where rates currently top out at 8.2% of the value of production and is forecast to rise to $2.1 billion in the year ending June 2013 after the hikes come into effect.

The price of December gold added $52.50 or 2.9% to trade at $1,870.30 an ounce in afternoon dealings on Thursday regaining much of the ground lost since hitting an intraday record of $1,923.10 an ounce on Tuesday. During August the metal added 12% as investors sought a safe haven from the slumping US economy and the continuing debt crisis in Europe. The ECB on Thursday decided to keep interest rates at 1.5% and cut forecasts for growth in the euro area while in the US jobless claims came in worse than expected. Bullion was also boosted by comments from the US Federal Reserve chief Ben Bernanke who all but confirmed a new round of stimulus will be announced at a meeting later this month.

A day after reports that the Canadian federal police have joined the investigation into who may be behind an anonymous letter alleging fraud at Silvercorp Metals from an apparent short seller, shares in the company were racing ahead 10% in brisk noon trade on Thursday. Silvercorp was forced last week Friday to make public the letter and at the same time disclosed that someone had built up a short position of 23 million shares – more than 13% of the number outstanding. The firm with projects in China and Canada plunged 10% after the news broke, but is now up a net 8.7%, helped along the way by an influential investment site that in rather dramatic fashion asks whether Silvercorp is the "perfect stock."